Definition 9 
Action classification score. Generated temporal proposals are fed to action classifiers to produce a probability distribution over all action classes. This can be represented by vector \((p^{1},\cdots ,p^{C})\)  where \(p^{i}\)  is the probability of action class \(i\) , and \(C\)  is the number of classes. For a fair comparison, researchers utilize classifiers from earlier work SCNN-classifier [1]}, UntrimmedNet [1]}, [3]}, etc. They uniformly sample a constant number of frames from the video segment and feed it to ConvNets such as C3D [4]}, two stream CNNs [5]} or temporal segment networks [6]}. In some cases, the recognition scores of sampled frames are aggregated with the Top-k pooling or weighted sum to yield the final prediction.

